Figure 4

Early levels of IL-8 are reduced in PBECs from healthy smokers versus COPD patients, induced by PMA and slightly sensitive to TAPI-2. Cells were growth factor-deprived overnight, pre-treated with medium TAPI-2 (2.5 μM) for 30 min and incubated with medium, CSE (2.5%) or PMA (5 ng/ml) for 2 hrs. A) IL-8 levels are significantly reduced in PBECs from smokers versus non-smokers and COPD patients under basal conditions. Absolute values and medians are shown. Significance is indicated (* = p < 0.05 and ** = p < 0.01). B) IL-8 mRNA expression was determined by real-time PCR. IL-8 Ct values were subtracted from β-actin Ct values, thus lower ΔCt values reflect lower mRNA levels. ΔCt levels and medians are shown. Significance is indicated (* = p < 0.05 and ** = p < 0.01). C) PMA increases IL-8 release in PBEC from the 3 different subject groups, which can be inhibited by TAPI-2. Absolute values are shown and significance is indicated (* = p < 0.05 and ** = p < 0.01). D) TAPI-2 significantly inhibits basal IL-8 levels in PBECs from non-smokers and healthy smokers, but not from COPD patients. Absolute values are shown and significance is indicated (** = p < 0.01).